The scaphoid is one of 8 small bones in the wrist joint, called carpal bones, which together allow the wrist to bend normally. The carpal bones form two rows across the wrist, and the scaphoid bone is an important connection between those two rows that is instrumental for full and painless motion.
Scaphoid fractures commonly occur following a fall onto the hand or wrist. A broken scaphoid bone typically produce pain along the thumb side of the wrist, which is worse when pressure is applied or when trying to bend the wrist. The pain may subside after several weeks or months, resulting in many patients believing they just suffered a “sprain”.
If you have pain in your wrist after a fall, x-rays are important to rule out a fracture. Delayed treatment can make can cause healing problems. The scaphoid bone has a tenuous blood supply. The normal blood flow to the bone can be disrupted by a fracture that shifts the bone. Additionally, if a diagnosis is not made and the wrist is used normally, the motion across the fracture site can prevent the two pieces from healing together normally. Sometimes, x-rays do not show the fracture immediately after the injury if the fracture is not displaced. When there is pain in the area of the scaphoid, repeating an x-ray 1-2 weeks later or having an MRI or CT scan can be helpful to make a diagnosis.
- Many “non-displaced” scaphoid fracture will heal uneventfully with 6-8 weeks in a cast that immobilizes the thumb and wrist.
- Fractures that have shifted, or “displaced”, are oftentimes treated surgically. The two fracture pieces are lined up, and a screw is placed within the bone to both stabilize the fracture and “compress” the two pieces together. This can increase the chance of healing.
- Typically after surgery, a cast or splint is maintained for 6-8 weeks, or until the fracture has healed
- Occasionally a scaphoid fracture is not diagnosed at the time of injury. If the fracture is not treated and the wrist is used normally, the motion across the fracture site can prevent the fracture from healing.
- A fracture that has not healed is called a non-union
If a non-union is caught early, before arthritis changes have taken place, it can be surgically treated.
In cases of delayed treatment, or “non-unions”, bone graft is often taken from the distal radius bone to help healing. Sometimes this bone graft is taken with its own blood supply, called a “vascularized” bone graft.
When a scaphoid is deprived of blood supply for a long period of time, the bone becomes avascular and necrotic (dead). This changes the shape of the bone, which over time results in arthritis throughout the surrounding bones of the wrist.
This pattern of arthritis is known as Scaphoid Non-union Advanced Collapse, or SNAC wrist.
If you are a smoker, it is very important to quit to maximize the chance of healing. Nicotine constricts blood vessels, which decreases the blood supply to the fracture site and dramatically decreases the body’s ability to heal the fracture.